uMap lets you create a map with OpenStreetMap layers and embed it in your site. All within a few minutes. You can create custom maps (see the examples at the instances' front pages). It is powered by open source, WTFPL-licensed software.

See also

ShareMap is a flash based online tool to create geometric elements on a background map (OSM among others), display GPX or KML files, import elements from OSM API via overpass-api and finally save the result in different formats for different purposes.